Redistribution of blood flow in acute hypometabolic behavior

Abstract

Cardiac output, renal and hepatic blood flows, arterial lactate concentration, and minute volume were measured before, during, and after 40 min of rest induced either by the practice known as "transcendental meditation" (TM) or by an ordinary eyes-closed rest-relaxation period. Two groups of normal young adults were studied: one group consisted of regular practitioners of TM and the other of similar individuals studied prior to learning this technique. Marked declines of renal blood flow were noted in both groups. Decline of hepatic blood flow, increased cardiac output, decreased arterial lactate, and minute volume were also recorded in the TM-induced rest period. These changes imply a considerable increase of nonrenal, nonhepatic blood flow during TM (44%) and, to a lesser extent, during rest (12%). Increased cerebral and/or skin blood flow is hypothesized to account for part of the redistributed blood flow in the practitioner.

Hormonal control in a state of decreased activation: Potentiation of arginine vasopressin secretion

“…It should be noted, however, that retrograde transport of pttuitary hormones back Into the brain may provide an explanation [7] Based upon evidence this ability ol peripherallyadministered AVP and its analogs to modify human and animal behavior, it is tempting to speculate that increased peripheral AVP achvity may mediate reported effects of TM on learning, memory, and psychotherapeutlc processes I I 1, 12,32], and that the mechamsm of its increased secretion m me&tation may be more specifically related to its role as a psychochemical. Their data also further support previous research in&cating specificity of TM (in the very long-term subject) among rest states in ~ts effects on hormones, metabolism, and circulation [17][18][19][20] …”

“…The first alternative is unlikely for several reasons. AVP is primarily cleared by the liver and kidneys, and previous study [19] of the distribution of blood (0----0).…”

“…The first alternative is unlikely for several reasons. AVP is primarily cleared by the liver and kidneys, and previous study [19] (0----0).flow during meditation and rest found no difference of hepatic/renal blood flow between meditation and rest prior to the eyes-closed meditation]rest period. Although a 40% decline of hepatic blood flow during meditation was reported (with a 12% non-significant decline during rest), this decline would be expected to increase AVP values acutely by a maximum of 70% during or after meditation, assuming an 18 min halflife for AVP in whole blood and a secretion rate averaging 2000/~U/15 minutes [26].…”

“…The purpose of the present study was to determine if long-term, regular practice of the technique of "transcendental meditation" (TM), reported to induce numerous behavioral changes [10,12,16,22,28], may be associated with altered secretion of AVP. This behavior, elicited twice daily in the morning and evening for 20--40 minute periods by the regular practitioner, is associated with major physiologic changes in long-term subjects [17][18][19]. …”

Modulation of red cell metabolism by states of decreased activation: Comparison between states

“…The TM subjects of these investigations are longterm practitioners. Whereas the results of early research studying only whole body respiratory change were consistent with physiologic similarity of TM and rest, more recent measurements---specifically on TM subjects who have now been eliciting this behavior for 5-10 years---indicate development of other fundamentally different hormonal, circulatory, and electrophysiologic changes [7,[11][12][13][14]18] in this group. Since participation of a humoral agent(s) in the TMinduced decline of red cell glycolysis is likely [12], it is possible that repeated elicitation or some special feature of this behavior is necessary for elaboration of the responsible effector.…”